One of the most striking things about Brexit has been that so far it has been debated, however rancorously, through the medium of normal politics. Yes, the EU referendum in 2016 was unusual, but it was hardly a constitutional innovation. Tempers have run high, there have been all kinds of argy-bargy in the House of Commons, but the British constitution—the political “rules of the game”—has broadly held.

All that changed two weeks ago. The question is, what does it mean?

First, it’s important to be clear again why the Speaker’s decision to accept the Grieve amendment, dictating the pace at which Brexit legislation is moved, really matters. The Speaker’s authority derives from his position as the elected nominee of MPs, his adherence to expert legal advice, and his neutrality. None of these was in play here: he acted on his own personal authority, against expert advice, and apparently not in a neutral way.

Some people have said, in effect: “There has been a lot of constitutional skulduggery on all sides so far. So what?” But this argument does not work.  Yes, party politics can fray the understandings and trust that underlie the British constitution. But changes made on purely personal authority by a Speaker to the rules of procedure of the House of Commons strike directly at its heart.

It’s also said that this was a democratic act. But the truth is that in many ways it was the exact opposite. It overturned the agreed rules of Parliament without notice, without previous deliberation and apparently without reflection on the precedent created, or its potential effects. It also undermined the status of the Clerks. Why should any MP or Government seek a ruling from them as to the correct legal procedure now, when the Speaker may simply decide to change the rules?

Indeed, to put the issue at its most philosophical, what is correct legal procedure, if the Speaker is making decisions as he alone sees fit?

Now today in the Commons amendments have been laid regarding Brexit which would potentially undermine the established constitutional basis of British government.  Their implications have been analysed for Policy Exchange by Sir Stephen Laws QC, former First Parliamentary Counsel (2006-12) and a Parliamentary draughtsman from 1976. That is, by someone with an extremely intimate understanding of Parliament and the constitution.

Specifically, see his recent papers “The Contest to ‘Take Control’ of Brexit” and “The Risks of the Grieve Amendment to Remove Precedence for Government Business”.

The risk is that the elected Government of the day will not be able to manage the flow of its business in Parliament, including manifesto commitments. But that opens up a host of further dire possibilities.

If Sir Stephen is right, these changes have the clear potential to strike at the heart of our constitution, with very serious consequences. Whether one agrees with his exact diagnosis or not, the constitutional centrality of these issues cannot be in doubt.  His papers should be circulated, read and considered as widely as possible.

People have voted in general elections in this country for more than a century on the basis that the elected Government of the day has the democratic right to put its business, including manifesto commitments, to the Commons ahead of other petitioners. These changes could destroy that.

More deeply, since the constitutional shift of 1688 the great achievement of British politics has arguably been in its movement towards what David Hume described as “a government of laws, not of men”.

Our constitution has evolved a unique combination of flexibility and authority, which has been widely envied and imitated. In general, contrary to various reports, it still works remarkably well. These actions would put that achievement at risk.  And the central point of the British constitution is to allow the passions of politics, referenda or no, to be channelled through Parliament. Parliament may or may not do a good job, from time to time. But people undermine it at their peril. And, of course, all of ours.

Jesse Norman MP is the author of acclaimed biographies of Edmund Burke (2013) and Adam Smith (2018)